Jumper Cables Can "Fry" Your Car

Posted by Battery Tender | February 8, 2018 2 Comments

Jumper Cables Can Fry Your Car

Statistically, February is the coldest month of the year – Watch out! We’re almost at the peak of winter. That means more engines that won’t start and calls to the office to tell your boss that you’re going to be late.

Cold weather is hard on vehicle starting systems, but there are other potential dangers you need to be aware of when you’re trying to get your engine started.


Newer cars are full of sensors and a computer system that controls almost everything. The biggest danger when using jumper cables on a newer vehicle is that the car with the ‘healthy’ battery will suddenly send too much voltage.

If the power surge happens, it won’t happen once you try to start the engine, it’ll happen right as the jumper cables are connected between the two vehicles. It’s at that moment that the unexpected surge in electricity can “fry” sensors or worse, the onboard computer


  1. We always recommend that you check your vehicles owner manual for instructions on how to properly jumpstart your vehicle. Every owner’s manual should have a step-by-step guide on how to jumpstart your engine.
  2. We recommend reading and knowing the steps even if you called for roadside assistance. Car enthusiast forums are full of stories of technicians unwittingly and accidently damaging vehicle electronics while trying to help. Making sure that you or your roadside technician follows the correct steps could save you thousands of dollars.
  3. Use a rechargeable portable jump pack. These jump packs come in many sizes but they are all designed to help you jumpstart your vehicle without having to call for roadside assistance or to use jumper cables connected to another vehicle.


It’s a good rule of thumb to stay away from the engine block when you’re jump-starting a car but we want to emphasize that this is also true when using a jump pack too. Never stand over a battery while the car is being started with a jump starter and make sure you are away from the battery.

All Battery Tender® jump starters are spark proof and reverse polarity protected. This ensures that they won’t shoot sparks out when you connect the unit to the car and that you can’t connect to the vehicle incorrectly and damage it. Each device also has a connection status indicator.

Despite these safety features, if you are not the one in the cabin starting the car, please step away from the car. This is another layer to ensure your own safety.


Being able to jumpstart your vehicle without calling for help will save you time and can help you stay safe. They are also less likely to damage your vehicle than jumper cables. We believe that having a portable jump starter is a safety feature and all drivers should have one, especially those that live in areas where it gets cold during the winter.

Click here to learn about the Battery Tender® line of portable jump-packs.

Topics: battery, battery maintenance, dead battery, cold weather, battery damage, battery recovery, jumper cable, jumper cables, jumpstart, onboard computer